This implements waiting for pending preloads, where the preload request
is still fetching the result when the second "real" request is started.
It is
implemented by storing responses in the `SharedPreloadedResources`
which is communicated via `PreloadId` send to the `CoreResourceManager`.
Part of #35035
---------
Signed-off-by: Tim van der Lippe <tvanderlippe@gmail.com>
Signed-off-by: Josh Matthews <josh@joshmatthews.net>
Co-authored-by: Josh Matthews <josh@joshmatthews.net>